(a) Structure-based alignment of NDPK sequences. The secondary structure is that of Ynk1. The homologous proteins are from Saccharomyces cerevisiae, Homo sapiens, Escherichia coli and Myxococcus xanthus. The alignment was drawn using ESPript (Gouet et al., 1999 ▶). (b) Ribbon diagram of a monomer of Ynk1; secondary structures are coloured cyan (helices), magenta (strands) and wheat (loops). This figure was prepared using PyMOL (DeLano, 2002 ▶).